week 7 lecture 4

Question 1

what are the function of the kidney?

Answer 1

excretion-metabolic products and foreign substances urea, uric acid and creatinine or drugs
regulation- body fluids, electrolytes and acid-base substance
control- blood pressure
secretion- hormones-erythropoietin and renin

Question 2

anatomical structure of kidney

Answer 2

slide 6

Question 3

blood supply to the kidney

Answer 3

renal artery- segmental artery- interlobar artery- arcrutae artery- interlobular artery- afferent arteriole- glomerular capillaries- efferent arterioles- peri tubular capillaries- interlobular veins- actuate veins- interloper veins- renal veins

Question 4

anatomical differences between the male and female bladder and urethra

Answer 4

detrusor, trigone, internal sphincters, external sphincters,

bulbousurethra gland

Question 5

function of detrusor muscle

Answer 5

allows pressure build up to signals the brain to urinate

Question 6

function of trigone

Answer 6

stretch to limit of expansion that signals the brain to urinate

Question 7

function of internal sphincters

Answer 7

allows involuntary control to prevent urination

Question 8

function of external sphincters

Answer 8

voluntary control that prevent urination

Question 9

function of bulbourethral gland

Answer 9

secrete lubricating fluid to the sperm to promote survival

Question 10

nephron structure

Answer 10

glomerulus-bowman capsule-PCT- descending and ascending loop of Henle- DCT and collecting duct

Question 11

cell types and location in the kidney and which are rich in mitochondria

Answer 11

epithelial cells in PCT and Loop- rich in mitochondria
principal cell- low in mitochondria
intercalated cell- rich in mitochondria

Question 12

types of nephron, their features and ratio of occurence

Answer 12

superficial nephron and juxtamedullary

occurrence is 10:1 ration

Question 13

why cortex granular while medulla striated

Answer 13

close packing of the glomerulus in the superficial nephron makes it have a granular appearance

Question 14

constituents of juxtaglomerular apparatus and function

Answer 14

juxtaglomerular cells- regulates the blood pressure by secreting renin
macula Densa-GFR regulation through tubulo-glomerular feedback mechanism
extraglomerular messangial cells

Question 15

glomerular filtration features adaptations

Answer 15

presence of fenestration, basal membrane, slit and slit diaphragm

Question 16

diameter of the slit diaphragm

Answer 16

70nm

Question 17

mechanism of glomerular filtration pressures

Answer 17

hydrostatic pressure from the aorta forces the plasma fluid out against the oncotic pressure and the hydrostatic pressure of the Bowman’s Capsule fluid

Question 18

how to calculate the net ultrafiltration pressure

Answer 18

net ultrafiltration pressure= pressure glomerulus- oncotic glomerulus - hydrostatic bowman

Question 19

what is the GFR?

how to calculate GFR

Answer 19

Glomerulus filtration rate-meaning the amount of filtrate passing from the glomerulus to the bowman capsule per unit time
GFR= pressure net ultra-filtration x constant Kf
affected by surface area and membrane permeability

Question 20

values of GFR for healthy male and female

Answer 20

90-140 mL/min in males and 80-125mL/min in females

Question 21

causes of a fall in GFR

Answer 21

renal disease with build up of excretory products

Question 22

how is the GFR regulated

Answer 22

myogenic mechanism- increase vessel resistance in response to increase BP in arteriole and tubule-glomerular feedback mechanism- decrease ATP and adenosine discharged in response to macula densa

Question 23

what’s renal clearance? and how to calculate it

Answer 23

amount of plasma that is completely cleared of a particular substance per unit time
conc. in urine x urine flowrate over conc. in plasma

Question 24

what does freely filtered means?

Answer 24

same concentration of substance passing through the blood and the bowman capsule as filtration process

Question 25

how to calculate GFR for freely filtered molecule

Answer 25

measuring the renal clearance of the melecule

Question 26

what molecule used for free filtration | which one is most commonly used

Answer 26

inulin and creatinine creatinine is most commonly used as the inulin is not found in mammals and therefore should be infused, meaning it is short-lived

Question 27

what assumption is made when using creatinine?

Answer 27

muscle mass is unchanged and therefore secretion is constant | the amount of creatinine secreted into the PCT is negligible

Question 28

what is indicated by low renal clearance of creatinine or high plasma creatinine

Answer 28

renal failure

Question 29

why is creatinine not a perfect molecule

Answer 29

small amount secreted into the nephron

Question 30

what happens if total amount of a substance entering the kidney equals amount excreted

Answer 30

renal clearance is equal to the RPF

Question 31

explain the secretion and reabsorption in the renal tubule

Answer 31

draw diagram

Question 32

explain how creatinine works for GFR determination

Answer 32

amount renal clearance since the creatinine is freely filtered, having the same concentration as the plasma

Question 33

how to determine renal plasma flow

Answer 33

amount of plasma going into the kidney | total amount entering kidney equals excretion, then renal clearance is equal to RPF, using PAH

Question 34

how does PAH works?

Answer 34

PAH is completely removed from the plasma by filtration and secretion

Question 35

what is filtration fraction? How to interpret the results and the formula

Answer 35

ratio of the GFR to the RPF, aka amount filtered from the plasma that ends up in the bowman capsule

Question 36

transport mechanism in renal tubules for passive and active transport

Answer 36

passive- diffusion, osmoses and electrical gradient active- primary and secondary primary active-active transport through pumps or endocytosis secondary active- solute movement along electrochemical gradient move other solute along symport and antiport

Question 37

transport pathways

Answer 37

transcellular and paracellular

Question 38

what happens in the PCT

Answer 38

reabsorption of Na+ and HCO3- using carbonic anhydrase angiotensin II effect on Na+-H+ antiport number glucose symport reabsorption NaCl and water-67% glucose-100% urea 50%

Question 39

describe the reabsorption in the loop of Henle

Answer 39

15% in descending loop and 25% NaCl in ascending

Question 40

describe the reabsorption in the DCT

Answer 40

NaCl reabsorption and active Ca2+ reabsorption

Question 41

describe the reabsorption in the DCT and collecting duct

Answer 41

principal cells and intercalated cells functions

Question 42

participating pressures in glomerular filtration

Answer 42

blood- hydrostatic and oncotic | interstitial fluid- hydrostatic and oncotic

Question 43

principal cells control

Answer 43

Na+ and K+ reabsorption in response to aldosterone and ADH aldosterone-regulation of Na+ reabsorption through apical Na+ channel and basolateral Na+-K+ ATPase pumps ADH- increase apical aquaporins to control water reabsorption

Question 44

intercalated cells

Answer 44

maintain acid base balance alpha-intercalated cells-HCO3- reabsorption and H+ secretion Beta intercalated cells- HCO- secretion and H+ reabsorption